High definition and extended depth of field intraocular lens

ABSTRACT

A virtual aperture integrated into an intraocular lens is disclosed. Optical rays which intersect the virtual aperture are widely scattered across the retina causing the light to be virtually prevented from reaching detectable levels on the retina. The use of the virtual aperture helps remove monochromatic and chromatic aberrations yielding high-definition retinal images. For a given definition of acceptable vision, the depth of field is increased over a larger diameter optical zone. In addition, thinner intraocular lenses can be produced since the optical zone can have a smaller diameter. This in turn allows smaller corneal incisions and easier implantation surgery.

PRIORITY CLAIM

In accordance with 37 C.F.R. § 1.76 a claim of priority is included inan Application Data Sheet filed concurrently herewith. Accordingly, thepresent invention is a Continuation-in-Part of U.S. patent applicationSer. No. 14/686,233 entitled “HIGH DEFINITION AND EXTENDED DEPTH OFFIELD INTRAOCULAR LENS” filed Apr. 14, 2015. The contents of the abovereferenced application are incorporated herein by reference.

FIELD OF THE INVENTION

The invention is directed to the field of posterior capsuleopacification.

BACKGROUND OF THE INVENTION

The human eye often suffers from aberrations such as defocus andastigmatism that must be corrected to provide acceptable vision tomaintain a high quality of life. Correction of these defocus andastigmatism aberrations can be accomplished using a lens. The lens canbe located at the spectacle plane, at the corneal plane (a contact lensor corneal implant), or within the eye as a phakic (crystalline lensintact) or aphakic (crystalline lens removed) intraocular lens (IOL).

In addition to the basic aberrations of defocus and astigmatism, the eyeoften has higher-order aberrations such as spherical aberration andother aberrations. Chromatic aberrations, aberrations due to varyingfocus with wavelength across the visible spectrum, are also present inthe eye. These higher-order aberrations and chromatic aberrationsnegatively affect the quality of a person's vision. The negative effectsof the higher-order and chromatic aberrations increase as the pupil sizeincreases. Vision with these aberrations removed is often referred to ashigh definition (HD) vision.

Presbyopia is the condition where the eye loses its ability to focus onobjects at different distances. Aphakic eyes have presbyopia. A standardmonofocal IOL implanted in an aphakic eye will restore vision at asingle focal distance. To provide good vision over a range of distances,a variety of options can be applied, among them, using a monofocal IOLcombined with bi-focal or progressive addition spectacles. A monovisionIOL system is another option to restore near and distance vision—one eyeis set at a different focal length than the fellow eye, thus providingbinocular summation of the two focal points and providing blendedvisions.

Monovision is currently the most common method of correcting presbyopiaby using IOLs to correct the dominant eye for distance vision and thenon-dominant eye for near vision in an attempt to achieve spectacle-freebinocular vision from far to near. Additionally IOLs can be bifocal ormultifocal. Most IOLs are designed to have one or more focal regionsdistributed within the addition range. However, using elements with aset of discrete foci is not the only possible strategy of design: theuse of elements with extended depth of field (EDOF), that is, elementsproducing a continuous focal segment spanning the required addition, canalso be considered. These methods are not entirely acceptable as straylight from the various focal regions degrade a person's vision.

What is needed in the art is an improved virtual aperture IOL toovercome these limitations.

SUMMARY OF THE INVENTION

Disclosed is a virtual aperture integrated into an intraocular lens(IOL). The construction and arrangement permit optical rays whichintersect the virtual aperture and are widely scattered across theretina, causing the light to be virtually prevented from reachingdetectable levels on the retina. The virtual aperture helps removemonochromatic and chromatic aberrations, yielding high-definitionretinal images. For a given definition of acceptable vision, the depthof field is increased over a larger diameter optical zone IOL. Eyes withcataracts can have secondary issues due to injury, previous eye surgery,or eye disorder that would not be well corrected with normal IOLdesigns. Examples of eyes with complications include: asymmetricastigmatism, keratoconus, postoperative corneal transplant, asymmetricpupils, very high astigmatism, and the like. Because of its ability toremove unwanted aberrations, our virtual aperture IOL design would bevery effective in provided enhanced vision compared to normal largeoptic IOLs.

An objective of the invention is to teach a method of making thinnerIOLs since the optical zone can have a smaller diameter, which allowssmaller corneal incisions and easier implantation surgery. Eyes withcataracts can have secondary issues due to injury, previous eye surgery,or eye disorder that would not be well corrected with normal IOLdesigns. Examples of eyes with complications include: asymmetricastigmatism, keratoconus, postoperative corneal transplant, asymmetricpupils, very high astigmatism, and the like. Because of its ability toremove unwanted aberrations, the disclosed virtual aperture IOL designis effective in providing enhanced vision compared to normal large opticIOLs.

Another objective of the invention is to teach a virtual aperture IOLthat exhibits reduced monochromatic and chromatic aberrations, as wellas an extended depth of field, while providing sufficient contrast forresolution of an image over a selected range of distances.

Still another objective of the invention is to teach a virtual apertureIOL that provides a smaller central thickness compared to otherequal-powered IOLs.

Another objective of the invention is to teach a virtual aperture thatcan be realized as alternating high-power positive and negative lensprofiles.

Yet still another objective of the invention is to teach a virtualaperture that can be realized as high-power negative lens surfaces.

Another objective of the invention is to teach a virtual aperture thatcan be realized as high-power negative lens surfaces in conjunction withalternating high-power positive and negative lens profiles.

Yet another objective of the invention is to teach a virtual aperturethat can be realized as prism profiles in conjunction with alternatinghigh-power positive and negative lens profiles.

Still another objective of the instant invention is to overcome theselimitations by providing a phakic or aphakic IOL which simultaneously:provides correction of defocus and astigmatism, decreases higher-orderand chromatic aberrations, and provides an extended depth of field toimprove vision quality.

Another objective of the invention is to teach a virtual aperture thatcan be employed in phakic or aphakic IOLs, a corneal implant, a contactlens, or used in a cornea laser surgery (LASIK, PRK, etc.) procedure toprovide an extended depth of field and/or to provide high-definitionvision.

Yet another objective is to provide an IOL for eyes with complicationssuch as asymmetric astigmatism, keratoconus, postoperative cornealtransplant, asymmetric pupils, very high astigmatism, and the like.

Still another objective is to provide an IOL capable of removingunwanted aberrations to provide enhanced vision compared to normal largeoptic IOLs.

Another objective of the invention is to teach replacement of thevirtual aperture with an actual opaque aperture and realize the sameoptical benefits as the virtual aperture.

Other objectives and further advantages and benefits associated withthis invention will be apparent to those skilled in the art from thedescription, examples and claims which follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the basic method of reducing monochromaticaberrations using pupil size;

FIG. 2 (A&B) illustrates the basic method of reducing chromaticaberrations using pupil size;

FIG. 3 (A&B) illustrates the basic concept of the virtual aperture tolimit the effective pupil size;

FIG. 4 illustrates the virtual aperture as a high-power lens sectionintegrated into an IOL;

FIG. 5 illustrates the virtual aperture as a negative lens section;

FIG. 6 (A&B) illustrates the virtual aperture as a negative lens (orprism) section in conjunction to a high-power lens section;

FIG. 7 (A&B) illustrates using the virtual aperture to prevent thenegative effect of a small optic zone;

FIG. 8 illustrates lens A example of an oblong shaped optical zone andlens B example of a circular shaped optical zone;

FIG. 9 illustrates azimuthally symmetric radial profiles;

FIG. 10 illustrates symmetric radial profiles comparing elements A, B,C, D, & E;

FIG. 11 illustrates two-dimensional lens regions; and

FIG. 12 illustrates the geometry for one of the two-dimensionalhigh-power lenses.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Detailed embodiments of the instant invention are disclosed herein;however, it is to be understood that the disclosed embodiments aremerely exemplary of the invention, which may be embodied in variousforms. Therefore, specific functional and structural details disclosedherein are not to be interpreted as limiting, but merely as a basis forthe claims and as a representation basis for teaching one skilled in theart to variously employ the present invention in virtually anyappropriately detailed structure.

FIG. 1 illustrates a single converging lens 1 centered on an opticalaxis 2. An incident ray 3 is parallel to the optical axis and willintersect the focal point 4 of the lens. If the observation plane 5 islocated a further distance from the focal point, the incident ray willcontinue until it intersects the observation plane. If we trace allincident rays with the same ray height as incident ray 3, we will locatea blur circle 6 on the observation plane. Other incident rays with rayheight less than incident ray 3 will fall inside this blur circle 6. Onesuch ray is incident ray 7 which is closer to the optical axis thanincident ray 3. Incident ray 7 also intersects the focal point 4 andthen the observation plane 5. Tracing all incident rays with a rayheight equal to incident ray 7 traces out blur circle 8 which is smallerthan blur circle 6.

The optical principle represented here is that as the height of parallelincident rays is reduced, the corresponding blur circle is also reduced.This simple relationship is applicable to the human eye. Stated anotherway, for a given amount of defocus (dioptric error) in the eye, visionis improved as the height of incident rays is reduced. This principle isused when someone squints in an attempt to see an out-of-focus objectmore clearly.

The tracing in FIG. 1 is for a single wavelength of incident light. Forpolychromatic light, three wavelengths in this case, we have thesituation in FIG. 2 . It is well known for the components of the eye andtypical optical materials that, as wavelength increases, the refractiveindex decreases. In FIG. 2A, a converging lens 21 has optical axis 22.An incident ray 23 consists of three wavelengths for blue (450 nm),green (550 nm), and red (650 nm) light. Due to different indices ofrefraction for the three wavelengths, the blue light ray 24 is refractedmore than the green light ray 25, and the green light ray is refractedmore than the red light ray 26. If the green light ray is in focus, thenit will cross the observation plane 27 at the optical axis. Thechromatic spread of these three rays lead to a chromatic blur circle 28on the observation plane. In FIG. 2B, the incident chromatic ray 29 hasa lower ray height than the chromatic ray 23 in 2A. This leads to thesmaller chromatic blur circle 33 at the observation plane. Thus, just asfor the monochromatic of FIG. 1 , chromatic blur is decreased as thechromatic ray height is decreased.

FIGS. 1 and 2 illustrate that decreasing ray height (decreasing thepupil diameter) decreases both monochromatic and chromatic aberrationsat the retina, thus increasing the quality of vision. Another way todescribe this is that the depth of field is increased as the ray heightis decreased.

FIG. 3A illustrates a converging lens 34 with optical axis 2 andaperture 35. Incident ray 36 clears the aperture and thus passes throughthe lens focal point 37 and intersects the observation plane 38 where ittraces a small blur circle 39. Incident ray 40 is blocked by theaperture, and thus it cannot continue to the observation plane to causea larger blur circle 41. An aperture which limits the incident rayheight reduces the blur on the observation plane. In FIG. 3B weillustrate what we describe as a “virtual aperture”. That is, it is notreally an aperture that blocks rays, but the optical effect is nearlythe same. Rays 43 which propagate through the virtual aperture 42 arewidely spread out so there is very little contribution to stray light(blurring light) at any one spot on the observation plane. This is theprincipal mechanism of operation of the IOL invention. Occasionally, afew months to a few years following cataract surgery and IOLimplantation, a condition called posterior capsule opacification (PCO)develops over the clear posterior capsule and can interfere with qualityvision. The incidence of PCO has been reported to be in the range of 5%to 50% of eyes undergoing cataract surgery and IOL implantation.Treatment to remove the PCO often involves intervention with a Nd:YAGlaser to perform a posterior capsulotomy. In this case, the laser isfocused through the IOL to perform the capsulotomy. If the virtualaperture were instead opaque, such as a true aperture, then thistreatment would be inhibited. The disclosed virtual aperture isintentionally designed to provide the benefits of a small aperture whileat the same time allowing a YAG capsulotomy to treat PCO.

FIG. 4 illustrates a basic layout of an IOL which employs the virtualaperture. In this figure, a central optical zone 46 provides correctionof defocus, astigmatism, and any other correction required of the lens.Generally, for an IOL using a virtual aperture, the central optical zonediameter is smaller than a traditional IOL. This leads to a smallercentral thickness which makes the IOL easier to implant and allows asmaller corneal incision during surgery. The virtual aperture 48 ispositioned further in the periphery and the IOL haptic 50 is located inthe far periphery. The virtual aperture is connected to the optical zoneby transition region 47 and the haptic is connected to the virtualaperture by transition region 49. The transition regions 47 and 49 aredesigned to ensure zero-order and first-order continuity of the surfaceon either side of the transition region. A common method to implementthis is a polynomial function such as a cubic Bezier function.Transition methods such as these are known to those skilled in the art.

In the preferred embodiment, the virtual aperture zone is a sequence ofhigh-power positive and negative lens profiles. Thus, light rays whichintersect this region are dispersed widely downstream from the IOL.These profiles could be realized as sequential conics, polynomials (suchas Bezier functions), rational splines, diffractive profiles, or othersimilar profiles, as long as the entire region properly redirects and/ordisperses the refracted rays. The preferred use is smooth high-powerprofiles over diffractive profiles as this simplifies manufacturing theIOL on a high-precision lathe or with molds. As known to those skilledin the art, the posterior side of the haptic should include a squareedge to inhibit cell growth leading to posterior capsule opacification.

FIG. 5 illustrates another profile for the virtual aperture zone 51,namely a diverging lens profile. Note that this requires a thicker edgeprofile than the approach in FIG. 4 . In FIG. 6A we show a close up ofthe preferred high-powered alternating positive and negative lensprofiles with the incident and transmitted rays. FIG. 6B illustrates theeffect of combining the profile in 6A with either an underlying prism ornegative lens. In this case not only are the emergent rays scatteredwidely, they are directed away from the eye's macula, or central visionsection of the retina, again, at the cost of a wider lens edge.

FIG. 7A illustrates a high-power IOL 60, usually with a relatively smalloptical diameter and large central thickness. When the eye's pupil islarger than the optical zone, incident rays 64 can miss the opticentirely and only intersect the haptic 61 on their way to the retina 63.This situation would cause noticeable artifacts in the peripheral visionof the eye. Incident rays 62, which intersect the optic zone asexpected, are correctly refracted to the central vision of the retina.In FIG. 7B we illustrate the same optic, but now with a virtual aperture65 between the optic and the haptic. In this case, incident rays 64which intersect the lens outside of the optical zone, are dispersedacross the retina causing no apparent artifacts.

Taken together, these characteristics of an IOL which incorporates thevirtual aperture can accurately be described as high definition (HD) andextended depth of field (EDOF).

The basic layout of the virtual aperture IOL is illustrated in FIG. 4 .In the preferred embodiment, the diameter of the central optical zone 46is 3.0 mm and the width of the virtual aperture 48 is 1.5 mm. Thus, thecombination of central optical zone and virtual aperture is a 6.0-mmdiameter optic, which is similar to common commercially available IOLs.

Spherical, Toric and zero aberrations optic zone. A significant portionof cataract patients have astigmatism in their cornea. After removal ofthe crystalline lens, the remaining optical system of the astigmaticcornea eye is ideally corrected with a toric, or astigmatic lens. Forthese patients, the central optical portion of our lens is made toric toprovide improved visual correction. In addition, even though the opticalportion is small, there is still some amount of spherical aberrationsthat could be corrected. Thus, the optimally corrected optical zonewould provide spherical aberration correction for all lenses and toriccorrection for those patients who have corneal astigmatism.

The toric correction is easily made by those skilled in the art byproviding two principle powers at two principle directions which wouldbe aligned with the eye's corneal astigmatic powers.

The spherical aberrations for either the spherical or toric lens arecorrected by employing a conic profile on one or more surfaces of thelens. Such a lens is said to have zero aberrations as there are zeromonochromatic aberrations in the lens for an on-axis, distant object.The apical radius Ra of the conic profile is computed as usual for thedesired paraxial power of the lens. A conic constant K is then selectedbased upon the lens material index of refraction, the lens centerthickness, and the shapes of the front and back surface of the lens.

In the case where the correction is to be astigmatic, at least one ofthe lens surface shapes is biconic, having a conic profile in twoorthogonal principal directions. In the preferred embodiment, the toricoptic has an equal biconvex surface design where each surface isbiconic. The non-toric optic has an equal biconvex surface design whereeach surface is conic. In both the biconic or conic surface case, theoptimal conic constant K for the surfaces is determined using opticalray tracing known to those skilled in the art.

Multiple focal points. Some patients may prefer a multi-focal pointoptic providing vision correction for specific distances. One example isa bifocal optic which generally provides focusing power for both nearand distant vision. Another example is a trifocal optic which providesfocusing power for near, intermediate, and distant vision. In eithercase, to implement the multi-focal points IOL, the optical zone ismodified to yield these focal zones using refractive or diffractiveoptical regions and the virtual aperture remains outside the last focalzone.

In some applications, the virtual aperture can appear as an annularregion with optical zones on each side of the annular region. The shapeof the annular virtual aperture can also be free form, for example toaccommodate an astigmatic optical zone or non-symmetric haptic region.This is illustrated in FIG. 8 . In this Figure, lens A indicates anoblong shaped optical zone and so the inner contour of the virtualaperture must adapt to the shape. The inner haptic zone contour iscircular, so the outer virtual aperture contour is circular. In thisFigure, lens B depicts the optical zone as circular, so the virtualaperture inner contour is circular. The inner haptic contour is oblong,so the outer virtual aperture contour is oblong. In each case there aretransition zones between each of the zones to smoothly connect theregions so that no visual artifacts are introduced into the eye.Alternatively, the transition regions can be of variable width so thatthe inner and outer virtual aperture contours can be any desired shape.

The IOL designs contemplated here can be made of any biocompatibleoptical material normally used for IOLs including hard and softmaterials. They also can be manufactured using CNC machines or molds orother methods used to manufacture IOLs. The virtual aperture can beimplemented as a one-dimensional profile that is symmetric in theazimuthal direction or a two-dimensional profile that implements tinylens regions.

In FIG. 9 , illustrated is azimuthally symmetric radial profiles. Theprofiles can be all the same or adjusted in the azimuth direction. Theseprofiles can be refractive or diffractive in nature. Although, eightdistinct radial profiles are illustrated, the radial profiles arecontinuous in the azimuth direction. The radial profiles can havealternating positive and negative power, all positive power, or allnegative power sections. The connections between all the power regionsare smooth to prevent visual artifacts.

In FIG. 10 , illustrated are other symmetric radial profiles includecombinations of planar, negative power, and ramp base shapes in additionto or instead of the high-power curves indicated in FIG. 8 . Referringto FIG. 10 , element A depicts a simple plane base shape. In FIG. 10 ,element B depicts a negative power base shape. This generally negativepower curved profile can be represented by a portion of a sphere, aconic, or higher order curve such as a polynomial. FIG. 10 , element Cdepicts a segmented negative power profile of element B, where the curvehas been segmented similar to a Fresnel lens, to keep the overall lensthickness small. FIG. 10 , element D depicts a ramp base shape profileand FIG. 10 , element E depicts a segmented version of the ramp baseshape, where the ramp has been segmented similar to a Fresnel lens, tokeep the overall lens thickness small. Although the segmented profilesof elements C and E are illustrated with sharp discontinuities, inpractice, the boundaries of the segments are implemented using smoothfunctions such as filets or Bezier curves to prevent observableartifacts caused by the sharp discontinuities. Additionally, a smoothtransition region is placed between the optic zone and the virtualaperture as described elsewhere in this document. These base shapes canbe used in conjunction with or instead of the high-power features toimprove the effectiveness of the virtual aperture.

FIG. 11 illustrates two-dimensional lens regions oriented in a polarsampling. The high-power lenses alternate in positive and negative powerin both the radial and azimuthal directions. Two positive power lensesand two negative power lenses are illustrated in the figure. The actualgeometry of these two-dimensional polar lenses is on the order of theradial profiles.

Alternatively, the two-dimensional high-power lenses could be allpositive or all negative lenses. In this case, the high-power lenses areseparated by small smooth transition regions (for example, a continuouspolynomial interpolator such as a Bezier curve) to prevent visualartifacts. This is the preferred two-dimensional high-power lensstructure when there is more than one lens sample rate in the azimuthdirection. In this case, the individual lenses look like small pillowswhere the pillows are above the base surface for positive power lensesand are below the surface for negative power lenses.

FIG. 12 illustrates the geometry for one of the two-dimensionalhigh-power lenses. In the upper right portion of the figure we show afront view of the high-power lens. There is a central high-power opticalregion and a surrounding transition region. The radial extent of thisregion is given by r, the width of the transition region is given by t,and the azimuthal subtense is given by theta. In the lower left portionof the figure we show a side view of one of the profiles of the lens.The central part represents the high-power optical zone and the two sidecurves represent the transition zones. The interface between the opticalzone and the transition zones has zero- and first-order continuity. Atthe edge of the lens boundary, the transition is coincident with thevirtual aperture base shape (which is typically a vertical line on theIOL). At the edge of the lens there is also zero- and first-ordercontinuity between the transition curve (typically a polynomial curve)and the edge. The shape of this small high-power lens region is set sothat the radial extent r is approximately equal to the arc-length of thecenter portion of the region.

The central optical zone can be designed using standard IOL designconcepts to provide sphere, cylinder, and axis correction, as well ashigher-order correction such as spherical aberration control. Thesedesign concepts are known to those skilled in the art.

The preferred virtual aperture profiles illustrated in FIG. 4 havealternating positive and negative lens profiles with focal lengths onthe order of +/−1.5 mm. These lens surface profiles can be generatedusing conics, polynomials (such as cubic Bezier splines), rationalsplines, and combinations of these and other curves. The geometry of thelens profiles is selected to adequately disperse the transmitted opticalrays across the retina and at the same time be relatively easy tomanufacture on a high-precision lathe or with a mold process. It is alsopossible to place a smooth surface on one profile (for example the frontsurface) and the small high-power lens profiles on the other surfaceprofile (for example the back surface).

Using the preferred virtual aperture profiles illustrated in FIG. 4 ,the edge thickness of the IOL and the center thickness of the centraloptical zone can be quite small, even for high-power IOLs. The materialof the lens is the same as those used for other soft or hard IOLdesigns.

The IOL design provides very good, high-definition, distance vision andthe range of “clear vision” can be controlled by specification of whatis meant by “clear vision” (e.g., 20/40 acuity), and the relative sizeof the central optic zone and the virtual aperture width. A simpleequation [Smith G, Relation between spherical refractive error andvisual acuity, Optometry Vis. Sci. 68, 591-8, 1991] for estimating theacuity given the pupil diameter and spherical refractive error is givenin equation (1a and 1b).A=kDE  (1A)A=√{square root over (1+(kDE)²)}  (1b)

-   -   A=acuity in minutes of arc (A=Sd/20), that is, the minimum angle        of resolution    -   k=a constant determined from clinical studies, mean value of        0.65    -   D=pupil diameter in mm    -   E=spherical refractive error in diopters    -   Sd=Snellen denominator

The second equation is postulated as being more accurate for low levelsof refractive error, and gives a reasonable result.

For E=0, A=1 min of arc or 20/20.

Solving (1b) for E yields equation (2).

$\begin{matrix}{E = \frac{\sqrt{A^{2} - 1}}{kD}} & (2)\end{matrix}$Equation (1b) tells us the acuity A given the range of depth of field(E×2) in diopters and the pupil diameter D.Equation (2) tells the range of depth of field in diopters given theacuity A and the pupil diameter D. For example, for:

Acuity of 20/40, A=40/20=2 min arc

D=3.0 mm

k=0.65

$E = {\frac{\sqrt{2 - 1}}{0.65 \times 3.0} = 0.89}$Depth of field=2E=1.8 D. Using (1b),A=√{square root over (1+(0.65×3.0×0.89)²)}=2

The concept of the virtual aperture can be employed in phakic or aphakicIOLs, a corneal implant, a contact lens, or used in a cornea lasersurgery (LASIK, PRK, etc.) procedure to provide an extended depth offield and/or to provide high-definition vision. Also, it would bepossible to replace the virtual aperture with an actual opaque apertureand realize the same optical benefits as the virtual aperture.

It is to be understood that while a certain form of the invention isillustrated, it is not to be limited to the specific form or arrangementherein described and shown. It will be apparent to those skilled in theart that various changes may be made without departing from the scope ofthe invention and the invention is not to be considered limited to whatis shown and described in the specification and any drawings/figuresincluded herein.

One skilled in the art will readily appreciate that the presentinvention is well adapted to carry out the objectives and obtain theends and advantages mentioned, as well as those inherent therein. Theembodiments, methods, procedures and techniques described herein arepresently representative of the preferred embodiments, are intended tobe exemplary and are not intended as limitations on the scope. Changestherein and other uses will occur to those skilled in the art which areencompassed within the spirit of the invention and are defined by thescope of the appended claims. Although the invention has been describedin connection with specific preferred embodiments, it should beunderstood that the invention as claimed should not be unduly limited tosuch specific embodiments. Indeed, various modifications of thedescribed modes for carrying out the invention which are obvious tothose skilled in the art are intended to be within the scope of thefollowing claims.

What is claimed is:
 1. An intraocular lens for providing an extendeddepth-of-field, said intraocular lens comprising: an optical zonecomprising at least one anterior optical surface and at least onemultifocal region; a first periphery region comprising a virtualaperture, said virtual aperture comprising an anterior virtual aperturesurface; and a second periphery region comprising a haptic forpositioning the intraocular lens within an eye, wherein said hapticcomprises an outermost region of said intraocular lens; wherein a firstplurality of light rays incident on said anterior optical surface passthrough said optical zone to form an image on a retina; and wherein asecond plurality of light rays incident on said anterior virtualaperture surface are dispersed widely downstream from the intraocularlens towards and across said retina, such that said image comprises saidextended depth-of-field and further wherein said virtual aperturereduces monochromatic and chromatic aberrations in said image, whereinsaid virtual aperture comprises a profile that is symmetric in anazimuthal direction and wherein said profile of said virtual aperturecomprises at least one of a planar profile, a negative power profile, aramp base shape, or a high-power curve profile.
 2. The intraocular lensof claim 1, wherein said optical zone consists of a central opticalregion of said intraocular lens, wherein said first periphery regionsurrounds said central optical region, and wherein said second peripheryregion is separated from said central optical zone by at least saidfirst periphery region.
 3. The intraocular lens of claim 2, wherein saidcentral optical zone comprises at least one of bifocal optics, trifocaloptics and multifocal optics.
 4. The intraocular lens of claim 1,wherein said optical zone comprises a central optical region and aperipheral optical zone, wherein said first periphery region surroundssaid central optical region, wherein said peripheral optical zonesurrounds said first periphery region, and wherein said second peripheryregion is separate from said central optical region by at least saidfirst periphery region and said peripheral optical zone.
 5. Theintraocular lens of claim 4, wherein said central optical zone comprisesat least one of bifocal optics, trifocal optics and multifocal optics.6. The intraocular lens of claim 1, wherein said optical zone comprisesa central optical region and one or more peripheral optical regions toprovide said intraocular lens with at least one of bifocal, trifocal andmultifocal optics.
 7. The intraocular lens of claim 6, wherein at leastone of said one or more peripheral optical regions surrounds said firstperiphery region.
 8. The intraocular lens of claim 6, wherein all ofsaid one or more peripheral optical regions surrounds said firstperiphery region.
 9. The intraocular lens of claim 6, wherein said firstperiphery region surrounds all of said central optical region and saidone or more peripheral optical regions.
 10. The intraocular lens ofclaim 1, wherein said optical zone comprises one or more of a refractiveoptical region and a diffractive optical region.
 11. The intraocularlens of claim 1, wherein said optic zone is separated from said virtualaperture by a first transition region, wherein said first transitionregion comprises a variable width.
 12. The intraocular lens of claim 1,wherein said virtual aperture is separated from said haptic by a secondtransition region, wherein said second transition region comprises avariable width.
 13. The intraocular lens of claim 1, wherein said opticzone is separated from said virtual aperture by a first transitionregion, and wherein said virtual aperture is separated from said hapticby a second transition region, and wherein each of said first and secondtransition regions comprises a variable width.
 14. The intraocular lensof claim 13, wherein said optic zone is separated from said virtualaperture by a first transition region, and wherein said virtual apertureis separated from said haptic by a second transition region, and whereineach of said first and second transition regions comprises a variableshape.
 15. The intraocular lens of claim 1, wherein said virtualaperture comprises a profile that is symmetric in an azimuthaldirection.
 16. The intraocular lens of claim 15, wherein said profile ofsaid virtual aperture comprises at least one of a planar profile, anegative power profile, a ramp base shape, and a high-power curveprofile.
 17. The intraocular lens of claim 16, wherein at least one ofan anterior surface of said virtual aperture and a posterior surface ofsaid virtual aperture comprises said at least one of said planarprofile, said negative power profile, said ramp base shape, and saidhigh-power curve profile.
 18. The intraocular lens of claim 17, whereinboth of said anterior surface of said virtual aperture and saidposterior surface of said virtual aperture comprise said at least one ofsaid planar profile, said negative power profile, said ramp base shape,and said high-power curve profile.
 19. The intraocular lens of claim 17,wherein at least one of said anterior and posterior surfaces of saidvirtual aperture comprises an alternating positive-negative powerprofile.
 20. The intraocular lens of claim 1, wherein said virtualaperture is shaped to improve light scattering across said retina. 21.An intraocular lens for providing an extended depth-of-field, saidintraocular lens comprising: an optical zone comprising at least oneanterior optical surface and at least one toric region; a firstperiphery region comprising a virtual aperture, said virtual aperturecomprising an anterior virtual aperture surface; and a second peripheryregion comprising a haptic for positioning the intraocular lens withinan eye, wherein said haptic comprises an outermost region of saidintraocular lens; wherein a first plurality of light rays incident onsaid anterior optical surface pass through said optical zone to form animage on a retina; and wherein a second plurality of light rays incidenton said anterior virtual aperture surface are dispersed widelydownstream from the intraocular lens towards and across said retina,such that said image comprises said extended depth-of-field and furtherwherein said virtual aperture reduces monochromatic and chromaticaberrations in said image; wherein said virtual aperture comprises aprofile that is symmetric in an azimuthal direction and wherein saidprofile of said virtual aperture comprises at least one of a planarprofile, a negative power profile, a ramp base shape, or a high-powercurve profile.
 22. The intraocular lens of claim 21, wherein said atleast one toric region provides spherical aberration correction.
 23. Theintraocular lens of claim 21, wherein said at least one toric regionprovides correction for astigmatism.
 24. The intraocular lens of claim21, wherein said at least one toric region, when implanted in an eye,provides correction for both astigmatism in a patient with cornealastigmatism and spherical aberration correction.
 25. The intraocularlens of claim 21, wherein said at least one toric region consists of twooptical powers in two principle directions, and wherein said twoprinciple directions would align with a patient's eye's cornealastigmatic power.
 26. The intraocular lens of claim 21, wherein saidlens provides a vision correction for at least one of sphericalaberration and astigmatism, and wherein said vision correction isprovided by employing a conic profile or a bi-conic profile on at leastone surface of the lens.
 27. The intraocular lens of claim 26, whereinsaid at least one toric region has an anterior surface and a posteriorsurface, and further wherein each of said anterior and posteriorsurfaces of said toric region has a conic or biconic profile.
 28. Theintraocular lens of claim 27, wherein said conic or biconic profile ofeach of said anterior and posterior surfaces of said toric region isbiconvex.
 29. The intraocular lens of claim 21, wherein said virtualaperture comprises a profile that is symmetric in an azimuthaldirection.
 30. The intraocular lens of claim 21, wherein said virtualaperture is shaped to improve light scattering across said retina. 31.An intraocular lens for providing an extended depth-of-field, saidintraocular lens comprising: an optical zone comprising at least oneanterior optical surface and at least one optical region; a firstperiphery region comprising a virtual aperture, said virtual aperturecomprising an anterior virtual aperture surface; and a second peripheryregion comprising a haptic for positioning the intraocular lens withinan eye, wherein said haptic comprises an outermost region of saidintraocular lanes; wherein a first plurality of light rays incident onsaid anterior optical surface pass through said optical zone to form animage on a retina; and wherein a second plurality of light rays incidenton said anterior virtual aperture surface are dispersed widelydownstream from the intraocular lens towards and across said retina,such that said image comprises said extended depth-of-field and furtherwherein said virtual aperture reduces monochromatic and chromaticaberrations in said image; wherein said virtual aperture comprises aprofile that is symmetric in an azimuthal direction and wherein saidprofile of said virtual aperture comprises at least one of a planarprofile, a negative power profile, a ramp base shape, or a high-powercurve profile.
 32. The intraocular lens of claim 31, wherein the atleast one optical region is a toric region.